This invention relates to fuel dispensing nozzles of the type used to dispense gasoline for automobiles and the like, and more particularly, to an improvement to such a nozzle assembly by which fuel which condenses in a vapor return hose of the nozzle assembly can be readily extracted and returned to the fuel source to help reduce atmospheric pollution.
Gasoline dispensing nozzles of the type found in most service stations employ a spout insertable into the inlet of the filler pipe of an automobile's fuel tank. Because of environmental concerns, it is now a requirement in many locales that fuel dispensing nozzles be designed so fuel vapors which previously were allowed to escape into the atmosphere during filling are captured and returned to the fuel source. For this purpose, nozzles are equipped with a flexible bellows assembly which fits over the spout. The end of the bellows fits snugly against the mouth of the pipe so there is no opening for gasoline vapors to escape. See, for example, U.S. Pat. Nos. 4,031,930, and 4,016,910, which are assigned to Husky Corporation, the same assignee as the present application.
To return fuel vapors back to the source, the nozzle assembly is equipped with a vapor return line. However, fuel vapors occasionally condense in this line, and the condensed fuel needs to be drawn off or else the vapor return passage will be blocked and not work as intended. Various attempts have been made to correct this problem, but there is still a need for a simple, reliable, and cost effective solution.
Generally, there are a variety of methods by which vapors from gasoline are captured, and returned usually back to the underground tank. Thus, by utilizing means for achieving such, the vapors are prevented from escaping to the surrounding atmosphere, and are returned to the storage tank. Usually, vapor recovery systems are of two types. One is the vacuum assist system, that utilizes the generation of a partial vacuum created within the nozzle, by means of the flowing fuel passing through the nozzle during its dispensing, and this partial vacuum has a tendency to attract vapors back into the nozzle, either through a bellows arrangement used in conjunction with the nozzle spout, or through passage created between concentrically arranged nozzle spouts, which allows the partial vacuum to attract the vapors back into the spout, for return to, usually, the underground storage tank. A second system utilizes what is generally identified as the balanced pressure system, whereby when gasoline is pumped into the automobile fuel tank, the displaced air is forced back towards the emplaced nozzle, and forces the gasoline vapors to be captured and passed through the bellows type boot, for forced return back into the fuel line, and eventually back to the underground storage tank.
Examples of patents that disclose these types of systems, as previously reviewed, include the Walker U.S. Pat. No. 4,429,725, which shows the vacuum assist vapor recovery system, in addition to the Polson U.S. Pat. No. 4,351,375, which utilizes the direct force of the flow of the dispensed fluid to regulate the opening or closing of a vapor passageway, rather than the peripheral pressure generated by the fluid to attain such. The Pyle U.S. Pat. No. 4,232,715, discloses the use of concentrically formed nozzle spout, including vapor passageway, and which opens the vapor-recovery valve through the actuation of a plunger caused when the fill pipe of the vehicle has the nozzle pressed against it, when inserted for filling of the fuel tank. Other patents relating to vacuum assist for removing vapors include the McGahey U.S. Pat. No. 4,223,706, in addition to the Lasater U.S. Pat. No. 4,199,012.